Improvement in processes for waterproofing leather



UNITED STATES MATTHEW BIRD, OF LONDON, GREAT BRITAIN.

IMPROVEMENT IN PROCESSES FOR WATERPROOFING LEATHER.

Specification forming part of Letters Patent No. 172,908, dated February 1-, 1876; application filed December 9, 1874.

To all whom it may concern:

Be it known that I, MATTHEW BIRD, of the city of London, in the Kingdom of Great Britain, have invented certain Improvements in Waterproofingand otherwise improving the conditiouof Leather, of which the following is a specification:

This invention relates to improving the condition of leather by chemical and mechanical treatment; and it consists in subjecting leather, in hides, skins, or pieces, to a bath consisting of a saturated solution with distilled water of equal parts of chloride of sodium and bicarbonate of soda or potash for any highly-tanned skins in-Which there is an excess of acid, or in a like solution oflower strength for skins not so highly tanned, previous to an after treatment,'whereby theleather is rendered waterproof, and at the same ti me material] ystrcn gthened in fiber and texture, and which treatment can be varied, so as to leave the-leather treated either rigid or pliant, according to the purpose for which it is required. I

Leather has been rendered water-proof by immersing it in a mixture of parafline with bees-wax, or the like. Although this is in 'generalan efiective process, I have found'that it is sometimes attended with failures, especially so when the leather is highly tanned;

and to overcome this difficulty, whichis the l object of my present invention, I immerse the hides, skins, or the like, first in a solution of I chloride of sodium and bicarbonate of soda 'orvpotash, which I find will render the leather I more susceptible to an after treatment by immersing it in a vat or vessel containing a mix- 1 ture of coal-tar pitch and solid paraffine. The -mixture consists of about seventy-five per cent. of solid paraffine, and about twenty-five .per cent. coal-tar pitch. These two substances are first dissolved by heat, and in separate vessels, and then the pitch is run into that containing the parafline, and the heat maintained until they become, by stirring, intimately mixed together. The heat of the mixture being still maintained, the leather, which has previously been heated in an oven to about 90 Fahrenheit, is, according to its substance or quality, either dipped intothe mixture, or allowed to remain in it for a few seconds or minutes, by which time it will have imbibed a sufficient quantity of the mixture. After complete absorption has taken place, the leather is rolled between brass, gun-metal, or wooden rollers or cylinders.

'Should it be judged that the leather has not absorbed to the full extent the mixture, it may, previously to the rolling process, be again placed in the oven, to insure thorough absorp- 7 then an application of parafliue, or paraffine and coal-tar, all substantially as and for the purpose stated.

' MATTHEW BIRD.

Witnesses:

[MATTHEW Aueusrus SoUL,

ALFaED JEFFERY.

PATENT Orrron. 

